Fix gsutil help for -o (#1271)
Fix gsutil help for -o (#1271)

* Fix gsutil help for -o

`-o`/`--option` takes a single mandatory parameter of a fixed form and this should be clear in the help
`-o` flags can be included more than once (as with `-h`).

* Wrap line
GoogleCloudPlatform/gsutil,GoogleCloudPlatform/gsutil